1. Field of the Invention
The invention relates to a compensating tank for a hydraulic motor vehicle brake system, having a housing comprising a housing upper part and a housing lower part and having a device for monitoring the tank filling level of the compensating tank, comprising a switching unit, which is welded to the housing and has a plug connector, and comprising a sensor or switching element which can be switched by means of a transducer at a switching point at which the switching unit generates a signal for an electronic control unit.
2. Description of the Related Art
In a hydraulic motor vehicle brake system, the required brake fluid is located in the compensating tank, with the device for monitoring the tank filling level having for example a reed switch as a switching element and for example a magnetic transducer as a transducer. If the brake fluid level falls and the magnetic transducer passes the switching point, then the switching contacts of the reed switch close. Said signal is evaluated in a control unit and the driver of the motor vehicle can be warned by means of a visual and/or audible indication. Here, it must be ensured that the compensating tank is always filled with a minimum level of brake fluid in order to permanently ensure the function of the brake system. Use is generally made of devices for monitoring the tank filling level, in which devices a float which is provided with a magnet switches the reed contact, which is arranged on a printed circuit board, when the float assumes a position (switching point) at which the tank filling level falls below a defined minimum. A warning signal which is perceptible to the driver is triggered by means of the reed contact, with suitable countermeasures then being initiated.
A generic compensating tank is known for example from DE 37 16 135 A1. The plug connector of the switching unit is provided in a plug connector housing which is welded to a side wall which projects from the plug connector housing. It is considered to be a disadvantage of the known compensating tank with regard to packaging and transport that the switching unit projects from the upper side of the compensating tank.
On account of the high filling pressures which occur when the motor vehicle brake system is filled with brake fluid on the production lines of automobile manufacturers, the demands made on the welded connections of the upper part and switching unit are becoming ever higher. The known compensating tanks no longer meet said demands, and leaks and shifts in the switching point occur on account of defective welded connections.